Reconstructing the size distribution of the primordial Main Belt

Abstract

In this work we aim to constrain the slope of the size distribution of main-belt asteroids, at their primordial state. To do so we turn out attention to the part of the main asteroid belt between 2.82 and 2.96~AU, the so-called "pristine zone", which has a low number density of asteroids and few, well separated asteroid families. Exploiting these unique characteristics, and using a modified version of the hierarchical clustering method we are able to remove the majority of asteroid family members from the region. The remaining, background asteroids should be of primordial origin, as the strong 5/2 and 7/3 mean-motion resonances with Jupiter inhibit transfer of asteroids to and from the neighboring regions. The size-frequency distribution of asteroids in the size range $17<D(\mathrm{km})<70$ has a slope $q\simeq -1$. Using Monte-Carlo methods, we are able to simulate, and compensate for the collisional and dynamical evolution of the asteroid population, and get an upper bound for its size distribution slope $q=-1.43$. In addition, applying the same 'family extraction' method to the neighboring regions, i.e. the middle and outer belts, and comparing the size distributions of the respective background populations, we find statistical evidence that no large asteroid families of primordial origin had formed in the middle or pristine zones.

References in corpus (13)

• Rapid planetesimal formation in turbulent circumstellar discs
• A low mass for Mars from Jupiter's early gas-driven migration
• Rapid growth of gas-giant cores by pebble accretion
• Asteroids Were Born Big
• Protoplanetary Disk Turbulence Driven by the Streaming Instability: Non-Linear Saturation and Particle Concentration
• Towards planetesimals: dense chondrule clumps in the protoplanetary nebula
• Protoplanetary Disk Turbulence Driven by the Streaming Instability: Linear Evolution and Numerical Methods
• Asteroid families classification: exploiting very large data sets
• The Size Distributions of Asteroid Families in the SDSS Moving Object Catalog 4
• Towards Initial Mass Functions for Asteroids and Kuiper Belt Objects
• Constraining the cometary flux through the asteroid belt during the late heavy bombardment
• Families among high-inclination asteroids
• The Dynamical Evolution of the Asteroid Belt

Cited by in corpus (18)

• Bifurcation of planetary building blocks during Solar System formation
• A water budget dichotomy of rocky protoplanets from ${}^{26}$Al-heating
• Turbulence sets the length scale for planetesimal formation: Local 2D simulations of streaming instability and planetesimal formation
• The Mass and Size Distribution of Planetesimals Formed by the Streaming Instability. II. The Effect of the Radial Gas Pressure Gradient
• An ancient and a primordial collisional family as the main sources of X-type asteroids of the inner Main Belt
• Spin states of asteroids in the Eos collisional family
• Super-Earths and Earth-like Exoplanets
• Exogenous origin of hydration on asteroid (16) Psyche: The role of hydrated asteroid families
• Asteroid cratering families: recognition and collisional interpretation
• Gaia search for early-formed andesitic asteroidal crusts
• Identification of a 4.3 billion year old asteroid family and planetesimal population in the Inner Main Belt
• A study of 3-dimensional shapes of asteroid families with an application to Eos
• Efficiency characterization of the V-shape asteroid family detection method
• Asteroid spin-states of a 4 Gyr collisional family
• Water transport throughout the TRAPPIST-1 system: the role of planetesimals
• Abundances of ordinary chondrites in thermally evolving planetesimals
• New Insights into Erg Chech 002 Analogues in the Main Belt from Near-Infrared Spectroscopy
• Search for L5 Earth Trojans with DECam